Crop sprayers are used to distribute a variety of chemicals, such as fertilizers, herbicides, and pesticides in a field where crops are grown. The crop sprayer includes a tractor with a boom arm or pair of boom arms that extend outward from the tractor. A number of nozzles are located along the boom arm. During a spraying operation, the chemicals are advanced through the nozzles as the tractor moves through the field.
In order to increase productivity of the spraying operation, the length of the boom arm is increased so that a greater area of the field can be covered during each pass of the tractor. However, increasing the length of the boom arm correspondingly decreases the maneuverability of the crop sprayer.
As the crop sprayer carries out a spraying operation, the boom arm may come into contact with an obstruction such as a tree, a telephone pole, or a fence post. Typically, the boom arm includes a bend away tip segment that deflects rearwardly as the tip segment of the boom arm comes into contact with the obstruction. The deflection of the bend away tip segment prevents the force of the collision from being transferred to the other parts of the boom arm and the tractor. However, a limitation to using a bend away tip segment is that damage is prevented only in collisions between the bend away tip segment and the obstruction.
The boom arm also includes an inboard boom arm segment secured to the tractor. Collisions between the inboard boom arm segment and the obstruction can potentially cause far more damage to the crop sprayer than collisions between the tip segment and the obstruction. For example, the hydraulic cylinders which are used to raise, lower, and rotate the boom arm are relatively expensive to repair or replace. These hydraulic cylinders are interposed between the tractor and the inboard boom arm segment. When the inboard boom arm segment comes into contact with the obstruction it is likely that one of the hydraulic cylinders will be damaged. The damaged hydraulic cylinder will require expensive repairs or replacement. Furthermore, if the collision occurs at a sufficient speed, the inboard boom arm segment and the associated mounting structure on the tractor may also be damaged. Because the inboard boom arm segment and the mounting structure are large and mechanically complex, replacement of the inboard segment or the associated mounting structure is costly and time consuming.
What is needed therefore is an apparatus and method for preventing damage to the inboard boom arm segment and the associated mounting structure on the tractor during a collision between the inboard boom arm segment and an obstruction.